24p questions

[Ash Greyson]

The default shutter, which is equal to a 180 degree shutter in film camera world, should be 1/48th in 24P, 1/60th in 60i and 1/60th in 30P. If you go at ANY other shutter speed you are adding a motion effect that cannot be reversed. The higher the shutter, the more jittery or crispy, the lower the shutter, the more blurry motion becomes.




ash =o)

[Jarrod Whaley]

Originally Posted by Ash Greyson

The default shutter, which is equal to a 180 degree shutter in film camera world, should be 1/48th in 24P, 1/60th in 60i and 1/60th in 30P.

I agree, it should be... but it isn't. The camera default in 30p is 1/30 (the shutter light comes on when you use anything else). Your default should probably be 1/60, unless you're going for one of the motion effects Ash describes.

[Ash Greyson]

By default, I dont mean what the XL2 goes to, I mean what YOUR default should be. It is also what the XL2 will go to in some of the auto modes. For that matter, the XL2 will default to 1/24th if you are in manual mode in 24P, pretty silly!



ash =o)

[Richard Hunter]

The PAL XL2 default in 25p is 1/25s too, i.e. the default power up shutter in Tv mode is 1/25s. It's now second nature for me to set the shutter after power up, but I must admit I shot a few blurry scenes before I got into the habit. Wish this default was user settable in a menu.

Richard

[Peter Vaughn]

Thanks for everyone's help yesterday on my 24P questions. However, I do have a few more. I'm trying to get a very sharp & detailed look in 24P for filming B-Roll inside of builder's model homes.
Here are my current settings:
24P
1/48 Shutter Speed
GAMMA: Cinema
KNEE: Middle
CONTRAST: Stretch
COLOR MATRIX: CINE
COLOR GAIN: +1
COLOR PHASE: -1
R GAIN: +2
G GAIN: -1
B GAIN +1
V DETAIL: NORMAL
SHARPNESS: +4
SET UP LEVEL +3
MASTER PED: -3
N.R: OFF

My footage still seems to be a little soft around the edges, & was wondering how to sharpen it up. Also, what are good settings for interviews to make the subject(s) sharp but to somewhat diminish the background...
Thanks for any input.
Peter Vaughn

[T.D. Jones]

Hi--

We've just shot some footage using two XL2s, so I was checking the settings for the pulldown mode in each. One of the cameras has the 3:2 mode selected, but the other has the mode selection pinked out inthe menu, which I presume means unavailable (it also doesn't change when you click the button). A cursory check shows all other settings on each camera to be the same.

Anybody know what this means?

TIA,

--Tim

[Justine Haupt]

The only thing I could possibly think of is that the fps select knob is set to either 30p or 60i (instead of 24p).

Anyone else?

[T.D. Jones]

No, that was the first thing I checked. I was tied up today (and tonight) but will do a thorough comparison of the settings on each camera tomorrow. If I discover the cause, I'll report back.

Thanks!

--Tim

[David Lach]

This might sound like a silly question, but I have never, ever been able to export 16:9 24p footage back to tape, and I was wondering if anybody here had a solution. I can't get it to work with Premiere Pro 2.0. Nor with Avid Xpress Pro. Nor with Vegas. It simply doesn't work, at least not with widescreen footage. I always get this weird aspect ratio jumping back and forth between 4:3 and 16:9 problem. When I re-import it sees it as 4:3 footage. It does this with both Premiere and Vegas. Avid, even worse, it exports as 4:3 footage and on top of it I have no sound going out and can only export with 3:2 pulldown, not 2:3:3:2 to be able to re-import and re-edit in 24p.

So I'm honestly at a loss here. I don't know what to do to export back to tape. I have 2 projects I'm currently working on that have been shot with the XL2 in 24p 2:3:3:2 mode and edited in Premiere with a 24p timeline. I can export a true 24p uncompressed AVI file. I can even export a 24p MPEG2 file. But I just can't get it back on tape in 24p. The only solution I found would be to export back as 29.97 regular NTSC. But I don't want to have to do that.

So how do you guys do it? Somebody out there has to have a successful workflow.

[Ash Greyson]

You cant export 24P to tape, you have to insert the missing frames. Premiere does this automatically, just check the Project Settings, then Playback Settings and then choose which conversion for 24P.

Sounds like you have other issues, I have never had any like you describe and I monitor to a firewire monitor so they would be pretty apparent. Are you sure all your settings are correct?



ash =o)

[David Lach]

Yes all my setttings are correct Ash. I know it adds a pulldown to conform to DV specs, but in my case, the process causes the aspect ratio to jump frantically every few frames between 4:3 and 16:9 footage. If I choose in Premiere Pro's project settings to have the aspect ratio conversion to be software based instead of hardware, it works, except it adds black bars on top and bottom instead of exporting true 16:9 footage. And if I choose no conversion well it just exports 4:3 footage.

I've heard others mention they had the aspect ratio conversion problem as well when exporting 24p with a pulldown added on the fly, I just don't know where it comes from and how it can be fixed.

I've had this problem on 2 different systems, one Intel the other AMD, no hardware component being the same, with the only similarity that both video cards were Nvidia GeForce based. My hardware is pretty new and powerful. I use a GeForce 7900 GT for video card and have a dual core Intel processor.

Just as a reference, can you tell me which video card you use, and if you use any other hardware acceleration cards?

[Ryan Black]

You need to configure your NLE to re-insert a pulldown pattern (2:3 / 2:3:3:2) to your 24p timeline when sending the video signal to something other than your computer screen (ie to throuugh firewire to your XL2 for viewing on an external broadcast monitor) If the XL2 receiveds the signal at anything other than 29.97, it will only display a stillframe, if anything.

I haven't used Vegas or Premiere for years, but check in your preferences to verify that when mirroring the video on an external monitor or when printing the timeline back to tape the necessary pulldown pattern is being applied.

As far as the audio, make sure it is either 32 or 48kz, and if more than two mono (stereo) channels, that your NLE is configured to downmix the tracks into just two channels. If you are doing 12 bit audio (32kz sample rate) the DV spec supports 4 channel audio, but I don't know of any NLE that supports capturing/exporting more than 2 at the same time to a miniDV device. You would have to do it in two passes.

Good Luck!

[Alan James]

I have had this same problem. The way I went about fixing it was to edit everything in Premiere 24p timeline then under the export settings set your compressor to “DV (24p advance)”. This is actually not 24fps its 29.97. This setting will add a 2:3:3:2 pulldown back into your footage so that at any point you can import it back into a 24p timeline and it will remove the added frames. After you have that file exported, create a widescreen 30p sequence and then import your exported 24p video into that. Being that your footage is really 29.97 with a pulldown and ur sequence is 29.97 they will play nice. Then from that sequence export the video to tape. There will be no loss in quality other then color timing. If you ever want to edit it again just pull it over to the computer as 24p footage and work in a 24p sequence. It will treat it as 24p because it has a 2:3:3:2 pulldown. Problem solved.

[David Lach]

Thanks for the suggestion Alan. Just to make sure here though, if you export as 30p (or 60i), even if the pulldown was correctly done, are you sure any NLE will see it as 24p material when re-importing? In other words, are the 24p flags that tell the NLE 1) that this is 24p material and 2) where to remove the fake frames to bring it back to 24p correctly applied? Because I understand that you can add a pulldown and export as regular DV but if the 24p flags aren't in there with the footage, no NLE will be able to recognize it as 24p footage.

Just wondering if you've actually tested for that.

[Alan James]

Don’t export as 30p or 60i straight from a 24p sequence. That will add a 3:2 pulldown to it and that wont work. I’m going to try to explain pulldowns and how NLEs treat them. I don’t know how big of an expert everyone is on this subject so I’ll try to explain as much as I can. If it is incoherent babble then just tell me and I’ll try to make it better.

Okay. To start with ALL frame rates are recorded to 60i. ALL. Because 30 is half of 60 there is no problem with storing progressive 30 on 60i. Same amount at data per frame and per second. Now 24p is different. The chips of your camera will fire at 24 fps but because all data is stored at 60i is has to add pulldowns. A 3:2 pulldown can’t easily be turned into 24p in a computer but a 2:3:3:2 pulldown can. So advance cameras can store 24p both ways. When you pull over footage your raw files are actually in 29.97 frame rate with a 2:3:3:2 pulldown added. When you import that footage into your NLE it quickly scans through the clip and figures out based off of interlacing and how the frame changes what frame rate it is and removes frames accordingly. So when u export your 24p footage using the 24p codec then re-import it into a 24p sequence the NLE again sees it as 29.97 with a pulldown and removes the pulldown.

So if you export you 24p footage using the 24p codec (turning it into 29.97 with a 2:3:3:2 pulldown) then import that into a 30p widescreen sequence the NLE will this time not care about interlacing and pulldowns because 60i and 30p are saved the same way. It will see it as what it really is, 29.97 with a pulldown. When you export that to tape it will export as the same because the frames will sync up. Now when u recapture it and edit in a 24p sequence the NLE will see the pulldown and remove it.

Might be confusing. The best way to see what I am talking about it to film different frame rates and capture them. Then in a 30p sequence go through them frame by frame and look at it at 100 percent magnification. You will see what I mean. Hope this helps.